Dual-motion advancing and resetting mechanism for relays



June 19, 1956 F c s 2,751,461

DUAL-MOTION ADVANCING AND RESETTING MECHANISM FOR RELAYS Filed March 29, 1951 2 Sheets-Sheet l i2 5 Q) 3% 13 lfi/enfor:

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June 19, 1956 5, co us 2,751,461

DUAL-MOTION ADVANCING AND RESETTING MECHANISM FOR RELAYS Filed March 29, 1951 2 Sheets-Sheet 2 650% 152 672 for:

fiau J'eoiaua United States Patent DUAL-NIGTHON ADVANCING AND RESETTING MECHANISM FOR RELAYS Frank G. Nicolaus, Chicago, 11, assignor to Raymond T. Moloney, Chicago, Ill.

Application March 29, 1951, Serial No. 218,147

16 Claims. (Cl. 200-105) This invention pertains to relays and like electromagnetically operated devices, and has as its principal object the provision for such devices of a dual-motion advancing and resetting mechanism having as one of its features a floating armature unit capable of dual motion, that is to say, capable of both reciprocation and a lateral rocking motion, to advance a ratchet and associated cam means to actuate various switches; and further operable in its rocking motion to release a holding pawl means for the purpose of resetting the ratchet and cam means.

A further object is the provision of a multi-position relay of simplified and economical construction, and having a novel armature construction in which a magnetically attractable portion of the armature also operates as a ratchet-advancing pawl and also cooperates with a releasing pawl for resetting purposes, and also straddles the latter pawl to hold the same in operative position.

Still other objects relate to the provision of an integrally formed ratchet and cam structure with a ratchet sector in one plane and a cam element situated in a parallel plane; and to the provision of a simple and inexpensive floating mounting for an armature unit, and a combination keeper and roller pin means for retaining the armature in assembled and operative position; and to certain adjustable mounting means for the switches.

Additional objects and aspects of novelty and utility relate to details of the construction and operation of the illustrative embodiment of the invention described hereinafter in view of the annexed drawings in which:

Fig. 1 is a side elevation of the relay;

Fig. 2 is a top plan view of the floating armature unit;

Fig. 3 is a top plan view of the relay;

Fig. 4 is a vertical sectional detail along lines 4-4 of Fig. 3 showing the parts in a normal or starting condition;

Fig. 5 is a view similar to that of Fig. 4 but showing the parts in an advanced condition of operation;

Fig. 6 is a fragmentary sectional detail, similar to that of Figs. 4 and 5, but showing the pawl means released for resetting;

Fig. 7 is an endwise elevational view looking in the direction of lines 7-7 of Fig. 1;

Fig. 8 is an elevational fragment with parts cut away to illustrate the switch adjustment relative to the switch cam;

Fig. 9 is an endwise elevational detail of the endwise slot mounting for the armature.

Referring to Fig. 1, the relay consists of a base plate 10 having opposite upset side flanges 11 and 12 and a short bottom flange 13, the flange 12 being further identified as the armature-mounting flange.

Riveted to the inside of flange 12 is an inner coilseating plate 14 (Figs. 2 and 3) having upset coil-seating lugs 15 engageable in the bore of a solenoid winding 16- A second or coil keeper plate 17, having seating lugs 17A, fits against the opposite end of the winding 16 and is removably secured to the base by screws 18.

One of the principal features of the relay structure I 2,751,461 lc Patented June- 19,. 1.956

pertains to a floating armature or core assembly, which is formed to operate also as a driving pawl, as will hereinafter appear.

This armature is generally indicated at 20 in Fig. 2, and consists of a pair of elongated bearing rods or straps 21, 22, of brass or other non-magnetic material.

Between the brass bearing straps is situated the armature-proper, generally indicated at 23, and consisting of a plurality of laminations 23A of so-called, electrical iron of good permeability, the straps and laminae being held in assembly by means of rivets 24; and a spring anchoring pin 25 is removably carried in a transverse bore in the assembly.

It will be observed in Fig. 2 that the opposite axial ends of the aforesaid armature assembly 23 terminate short of the ends of the flanking brass strap 21, 22, the two shorter projecting strap legs 26 at one end constitut ing a bearing means for a floating mount to be described further hereinafter, while the opposite pair of longer projecting legs 27 at the forward (upper end in Fig. 2) of the armature unit constitute the so-called free or operating end of the unit, for reasons to appear.

As depicted in Figs. 4 and 9, the floating armature pawl 20 is mounted for both rocking and reciprocable motion by projecting the shorter pair of legs 26 through a pair of slots 12A and 128 (Fig. 9 particularly) in the armature flange 12, these slots being sulficiently oversize to permit a certain rocking movement to be described, and the slot 128 being oversize laterally so as to allow for variations in the thickness of the armature laminations 23A.

As viewed in Fig. 1, the armature assembly 2t? is urged outwardly of the coil 16 by a spring 30, one end of which is anchored to the pin 25, and the other end of which is hooked onto a lug 11A of flange 11, the latter having (Figs. 6 and 7) a large cut-out or passage 11B therein and through which the free-end parts 27 project for cooperation with some resetting means.

The outward movement of the armature under urgence of spring 30 is limited by a stop and roller pin 28 (Figs. 3 and 7) fitted loosely across the free end region of the brass armature straps, and having a width exceeding that of the flange opening 11B.

Referring to Fig. 4, the ratchet sector 32 has an arcuate edge in which are formed ratchet teeth 33, the sector being pivoted on a pin 34 fixed in the base plate, the sector having integrally formed therewith a switch-operating cam 35' (Figs. 1 and 7) connected thereto by a bight or web portion 36, seen particularly in Fig. 7, so that the ratchet, and cam pieces are integral but lie in spaced parallel planes with the pivot pin 34 engaging both pieces.

A spring 36 (Fig. 1) normally urges the ratchet sector counterclockwise, and this motion is limited by an arcuate finger 32A, which serves as a stop by engaging the lower base-plate flange 13. i I

The laminar end section 23X of the armature assembly, as in Pig. 4, is offset downwardly from between the brass straps and serves as a pawl to engage in the ratchet teeth 33, it being noted (Fig. 1) that the pull of spring 30 tends to urge this pawl nose 23X down onto the teeth of the ratchet sector.

As in Fig. 4, a holding pawl 10 is pivoted on a base pin 41, and is urged downwardly by a coil spring 42 (Fig. 7 also) to ride upon the arcuate periphery of the ratchet sector and engage in the teeth 33 to hold the gain of the sector in advanced positions. 1

The holdin pawl as is of a width to fit freely in be tween the spaced brass bearing straps. 21, 22, of the armature, as seen in Fi s. 3 and 7, so that no other retaining means is needed to main ain his. p wl in assembled condition.

Moreover, the: pawl i0 is pitched downwa dly othat its lower end overlies closely the end or pawl portion 23X of the armature to afford a resetting or releasing arrangement which merely requires a lifting of the free end portion of the armature unit 20 to pivot the holding pawl 40 upwardly out of engagement with the ratchet teeth, as illustrated in Fig. 6.

It is contemplated that any suitable means may be employed for lifting the armature to effect a releasing or resetting of the relay; and in Fig. 7, one such means is disclosed as a link 45 having a lower offset end 46 which underlies the free end projection 27 of the armature unit, so that an upward pull on this link will elevate the end of the armature, causing it to rock on a fulcrum afforded by its opposite end portions 26 confined, somewhat loosely, in slots IZA-EZB.

The aforesaid upward movement of the resetting link 45 may be effected by an desired means; however, an electromagnetic solenoid it; provided for this purpose in the embodiment shown, as indicated in Fig. 6, the same having a plunger 48A connected to link 45.

The switching functions of the relay are effected through a plurality of switches 50, St and 52-, the same being in this embodiment of the type known as stack switches, each including a plurality of pairs of contact blades adapted to be connected to desired control circuits.

Each of said switches is provided with an operating blade adapted to be actuated by the cam 35, the operating blades for twoof the switches having cam riders 59A and 52A, respectively (Figs. 1 and 8) adapted to ride on the edge of the cam and to engage in cam formations or notches 35A or 353, and thereby effect various operations of the associated contact blade assemblies, depending upon the depth, length, and location of the notch formations 35A, 3513.

The third switch, 51, is operated by a pin 55 carried by the cam 35 and movable thereby (as in Fig. 5) down onto the topmost contact blade of the assembly.

An important feature of the switch means is the adjustability thereof, which is effected by providing in the flange 11, for example (Fig. 8), an elongated slot 11X in which the two bolts StiX may move in effecting a vertical adjustment of the switch 50 to position the operating portion 50A thereof properly relative to the cam notch 35A, for example. The other stack switch 52 is similarly mounted by bolts from the stack movable in a long slot to enable locating the rider 52A relative to notch 358.

Another feature of the mounting of switch 59 relates to the provision of a keeper 60 (Figs. l, 3 and 8) in the form of an angle bracket having two holes in one face tapped to receive the switch mounting bolts 50X, and having its other face situated, as in Fig. 3, to confine the stop and roller pin 28 of the armature against escape from its loose seat in the ends of the brass bearing straps.

Operation The normal condition of the relay is depicted in Fig. 1, the corresponding position of the ratchet sector being shown in Fig. 4.

Energization of the solenoid Winding 16, would attract the armature assembly toward the left, and the armature pawl 23X would engage in one of the teeth 33, so that upon return (toward the right) of the armature under the urgence of spring 30, the ratchet sector 32 would be turned a distance of one tooth, and the holding pawl 40 would hold this gain.

Similarly, each energization of solenoid 16 would produce a like advance, the number of possible steps being of course dependent upon the number of teeth 33 provided in the sector.

In the present embodiment, the relay has three positions: normal, and two steps from normal. While a variety of switching arrangements is possible, as will be understoodin the art, the present embodiment provides for a normal condition in which the two switch-blade riding parts 59A and 52A (as in Fig. l) are dropped into the cam notches 35A, 35B to produce a certain desired condition in the associated switches, and the cam pin 55 is turned away from the operating blade of the third switch 51, as in Fig. 4.

When the ratchet sector, and hence the cam 35, takes its first step from normal (not illustrated) the switch 52 is the first to be operated, its cam rider 52A rising at once out of notch 35B to ride the rise of the cam, as in Fig. 8; while the other switch rider 50A remains at its lower level by reason of the predetermined arcuate length of the root of notch 35A.

However, when the second step is taken, cam rider portion 56A also rises to the upper cam level, as in Fig. 8.

At this time, the cam pin 55 will have closely approached the operating or top blade member of its switch 51, but wili not yet have operativeiy engaged the same; but upon taking of the third step, pin 55 will bear down upon the operating blade, as illustrated in Fig. 5, to operate the third switch.

In order to reset the relay, it is merely necessary to raise the free or projecting end of the armature unit a sufficient distance from its normally depressed condition, Fig. 5, to the releasing or elevated condition of Fig. 6, as by energizing the reset coil 48, for example, thereby raising the plunger and link means 43A-35 so that the link offset 46 will bear up against the free end portions 27 of the armature unit and elevate the latter to the condition seen in Fig. 6, which results in a pivoting of the holding pawl 46 upwardly and away from the teeth 33 by impingement of the armature pawl or nose portion 23X against the underside of said holding pawl to release the sector and its cam for return to normal position by spring 36.

It may be observed from Fig. 6 that during such upward displacement of the free end region of the armature unit, the roller and stop pin 28 tends to ride against the flange 11, and being free in its seat in the straps 21, 2.2, this pin tends to turn and relieve some of the friction which otherwise arises from the stopping action of this pin in preventing escape of the armature through opening 1113.

In such releasing operations, the opposite or inner end region 26 of the armature assembly tends to rock in flange slots 12A and 12B, and in the sense that this armature unit is free to move back and forth, as well as rock up and down, or to perform both movements simultaneously, it is said to float; and this functional and structural character of the armature enables it to perform the dual functions of advancing and resetting the ratchet and cam means. This, in addition to such features as retaining the holding pawl in position by disposition in between parts of the armature itself, and employing the simple combination stop and keeper and nut bracket 60, and the ratchet stop finger 32A, makes possible a very economical construction which is easy to assemble or take apart.

For example, to remove the armature unit, the switch mounting screws 50X are backed out so that the bracket 60 is freed and pin 28 may be withdrawn, whereupon the armature unit 20 may be withdrawn (to the right) through the flange opening 11B.

If the coil 16 is to be replaced, screws 18 are removed, and the coil comes free and can be taken out by moving the armature far enough to the right, after removal of pin 28 as aforesaid.

Additional or difierent switch means may be employed for various applications, and the number of teeth 33 on the ratchet sector may be extended; and while the dualmotion armature means is especially useful in connection with a switching unit such as described, it is contemplated that said mechanism has utility in conjunction with instrumentalities other than the cam-operated switching means shown.

The electromagnetic actuating means, including the coil or solenoid 16 and the armature unit 20, is adapted for operation on alternating current, and the flanking brass bars or straps 21, 22, supporting the armatureproper as they do, out of all contact with the base plate or parts of the magnetic circuit, prevent sticking due to residual magnetism, and reduce the chatter and sluggishness armatures commonly exhibit in both direct and alternating current operations where there is iron-toiron contact, and while it is well known in the art to employ non-magnetic spacers for analogous purposes, the floating armature structure herein disclosed affords a novel construction in this, and other respects.

A peculiarity of the dual-motion armature means disclosed resides in the fact that the armature pawl is arranged in relation to the holding pawl so that should the armature unit be displaced laterally and axially inward of the solenoid at the same time, the holding pawl would not be released, it being intended in the illustrative embodiment that release can be effected only when the armature is at rest in normal position.

I claim:

1. In a relay, an elongated armature, a solenoid freely surrounding one end region of said armature, means at said end region mounting the armature for reciprocable and rocking motion, said solenoid having a bore wide enough to permit a predetermined range of rocking motion to the armature, means adjoining the opposite end region of said armature and movable both laterally and longitudinally therewith in said rocking and reciprocable motions thereof and defining a ratchet pawl, a ratchet pivoted at one side of said pawl to be advanced thereby responsive to reciprocations of said armature, spring means urging said armature lengthwise to a normal position outwardly of the solenoid and also laterally to engage said ratchet pawl with said ratchet, spring means urging said ratchet to a normal position opposite from the direction of advance thereof by said ratchet pawl, 21 holding pawl pivoted on a side of said ratchet pawl remote from the ratchet and spring-urged normally to engage and hold the gain of the ratchet in advancing direction, said armature being rockable to engage and move the holding pawl from the ratchet to release the latter for return to normal position, and switch means operably controlled by movements of said ratchet.

2. Apparatus according to claim '1 and further characterized by the provision of a switch operating cam formed integrally with said ratchet and offset therefrom to move in a plane parallel to that of the ratchet, said switch means including a plurality of switch members actuated variously by said cam dependently upon the posi tions into which the same is moved by said ratchet, said ratchet having a plurality of teeth engageable by said ratchet pawl to effect a plurality of advancing steps of the ratchet corresponding to a plurality of reciprocations of said armature, certain of said switch members being operated in certain of the advanced positions into which the ratchet is moved as aforesaid.

3. The construction defined in claim 1 and further characterized in that said armature has an open portion opposite said holding pawl and the latter projects through said open portion past said ratchet pawl into operative relation with said ratchet, said holding pawl being freely slidable on a pivot into and out of operative relation with said ratchet and being confined against escape from said operative relation by the c ircumambient margins of the aforesaid open portion of the armature.

4. For a relay or the like, a dual-motion advancing and resetting mechanism including a rotatable ratchet, a pivoted holding pawl spring-urged to engage the ratchet to hold any gain thereof, an armature unit including an elongated armature and a pair of longer straps flanking and attached to said armature with opposite end portions projecting beyond the ends of said armature, means affording bearings for the projecting end parts at one bearing end of said straps and permitting both axial-sliding and lateral-rocking motion of the armature unit, means guidedly supporting the opposite free end regions of said straps .for both axial and lateral movements as aforesaid, a solenoid having an oversize bore freely surrounding said bearing end region of the armature unit to permit both axial and lateral movements as aforesaid, spring means urging said armature unit outwardly and laterally of the solenoid to a normal position, stop means limiting outward movement of the armature unit, an advancing pawl part on said armature unit and engageable in said normal position of the latter with said ratchet to advance the same responsive to axial reciprocation of said unit, spring means urging said ratchet to a normal position in a direction opposite advancing movement thereof, said armature unit being movable laterally from said normal position to disengage the pawl part from the ratchet and to engage said holding pawl and pivot the same out of holding engagement with said ratchet freeing the latter for resetting said last-mentioned spring means, a control member movable by said ratchet in advancing movements, at least, of the latter, and switch means operably controlled by movements of said control member.

5. Mechanism according to claim 4 and further characterized in that said advancing pawl is an integral part of said elongated armature, and said straps straddle said holding pawl to permit the latter to overlie said integral advancing pawl such that the latter in rocking motion of the armature as aforesaid, will engage and pivot the holding pawl free of the ratchet as aforesaid.

6. Apparatus of the class described comprising a solenoid having a plate opposite one axial end of the bore thereof, said plate having a pair of spaced, elongated parallel slots therein confronting said bore, a joined pair of elongated non-magnetic straps having the opposite terminal portions at one bearing end thereof respectively seated in said slots, the latter being oversize to permit both sliding reciprocation of the straps and lateral rocking thereof with the slots as a fulcrum point, an elongated armature secured between said straps and spaced from the axial ends of the latter, said armature having a pawl part offset from between said straps, means limiting both movements of the straps at the ends thereof opposite from said bearing end thereof, spring means urging said straps to a normal position to position the armature a determined amount outwardly of the solenoid, ratchet means advanced by said pawl responsive to reciprocation of the armature by attraction thereof by said solenoid and opposite movement thereof by said spring means, and a holding pawl for the ratchet means and moved by lateral displacement of said straps and armature to disengage the ratchet means, and spring means normally urging said ratchet reversely from its advancing movement to a predetermined normal position.

7. In a multiposition relay of the type including switch means adapted to be actuated by rotatable cam means operable in different positions to actuate said switch means in a predetermined manner, together with a rotatable ratchet for driving said cam means, improvements comprising, to wit: a floating, elongated armature and means mounting the same for relatively independent axial reciprocation and lateral displacement, an advancing pawl part of'said armature and engageable with said ratchet to advance the same in axial reciprocation of said armature, electromechanical means operable to reciprocate said armature axially, holding pawl means spring-urged into holding engagement with said ratchet and positioned relative to said advancing pawl to be engaged and moved by the latter, responsive to a predetermined lateral movement thereof, to disengage the holding pawl means and free the ratchet, means for moving the freed ratchet reversely from any advanced position to a normal starting position, and electromechanical means for imparting lateral movement to said armature.

8. In an electromechanical ratchet mechanism, a solenoid, a member confronting one axial end of the bore of said solenoid and having therein elongated slot means, an armature unit comprising a pair of parallel bars of non-magnetic material, at least one of said bars having an endwise portion lodged in said slot means for axial sliding motion, said slot means being oversize to permit rocking of said bar portion therein, an elongated armature, shorter than said bars, and fixed in between, and in substantial parallelism with, said bars and the latter having a normal position displaced outwardly of said solenoid with a substantial portion, less than all, of said armature also disposed outwardly of the solenoid bore, spring means urging said armature unit to said normal position, said armature having a pawl formation offset outwardly and laterally from between said bars, a ratchet engaged by said pawl formation and moved by the latter responsive to reciprocation thereof with the armature and bars, releasable means for holding the advancing gains of said ratchet and engageable by a part of said armature unit in lateral motion thereof to be released, means for restoring the ratchet, when released as aforesaid, from advanced to a predetermined normal position, a controlled instrumentality actuated by movements of said ratchet, at least one of said bars having a free end portion, remote from the said slot-lodged portion thereof, projecting into position for coaction with a resetting member adpated to impart lateral displacement to said armature unit for the purpose of freeing the ratchet as aforesaid.

9. In an electromagnetic ratchet-operating mechanism, a solenoid, an elongated armature unit having one axial end region disposed in the bore of said solenoid, spaced supporting means guiding both end regions of said armature unit for axial reciprocation in the bore of the solenoid and also for lateral rocking motion relative to the axis of reciprocation thereof, combination stop and roller pin means seated loosely in, and projecting outwardly crosswise of, said armature unit near the end region thereof which is remote from said solenoid, and means including plate members, at least one of which is removable, guarding the two axial extremities of said pin means for removably retaining the latter in seated condition in the armature unit while permitting free movement thereof in said seat with the armature unit, said pin means limiting axial displacement of the armature unit in a direction away from said solenoid by engagement with that part of the aforesaid spaced supporting means which is at the end of the armature unit remote from the solenoid, ratchet means actuated by axial movement of the armature unit, and holding pawl means for said ratchet means and released by lateral movement of said unit.

10. An electromagnetic device comprising a toothed ratchet member to be advanced; a reciprocable pawl cooperable with the teeth of the ratchet member to advance the same; means mounting said pawl for substantially linear advancing motion to engage said teeth and advance the ratchet member, and for retraction to a starting position; said pawl-mounting means also permitting lateral movement of the pawl for slippage over the ratchet teeth in said retraction; means yieldingly urging said pawl in said advancing direction to said starting position and also yieldingly biasing said pawl laterally toward said ratchet teeth; an electromagnetic solenoid having an oversize bore surrounding a particular portion of said pawl; and an armature part on said particular portion of the pawl for attraction into said bore to move the pawl linearly, as aforesaid, and of such dimension to be freely movable in a lateral sense in the bore to permit lateral displacement for slippage of the pawl relative to the ratchet teeth as aforesaid.

11. In a ratchet mechanism an electromagnetic advancing-pawl structure for driving a ratchet member step-bystep, said structure including a solenoid, an elongated stroke arm having ratchet-pawl means at one end and an armature portion near an opposite end; said solenoid having a bore substantially wider than the width of said stroke arm and armature portion, means mounting said pawl for both longitudinal reciprocation and sidewise movement with said pawl means drivingly engageable with the teeth of said ratchet member so that the latter will be advanced by the pawl means responsive to longitudinal movement of the stroke arm in one direction, and said pawl means will move sidewise to slip back over the ratchet teeth responsive to longitudinal movement of the stroke arm in the opposite direction, and spring means urging said stroke arm to a normal position outwardly of said solenoid with said armature disposed a predetermined amount outwardly of said bore and said pawl means urged sidewise into cooperative relation to said ratchet teeth.

12. In an electromagnetic ratchet mechanism, the combination, with a toothed ratchet member, of electromagnetic drive means therefor comprising: a solenoid, an elongated stroke arm, means mounting one end portion of said arm near one end portion of the solenoid bore for both longitudinal reciprocation and rocking movement, said bore being oversize to permit both movements of said arm; armature means carried by said arm near said one mounted end portion thereof for attraction into said bore to effect longitudinal movement of said stroke arm; pawl means carried near an opposite end portion of said stroke arm in fixed condition relative to the latter for driving engagement with the teeth of said ratchet; and spring means urging said stroke arm both longitudinally and laterally to dispose said stroke arm in a predetermined starting position with said armature a predetermined amount outwardly of the center of said bore, and said pawl means disposed in driving alignment with said ratchet teeth; and selectively operable means for moving said stroke-arm sidewise to withdraw the pawl means from driving relation relative to said ratchet teeth.

13. In an electromagnetic ratchet mechanism, a ratchet member adapted to be advanced by a driving pawl in one direction; means normally and yieldingly acting to move the ratchet member in the opposite direction; releasably movable holding pawl means normally engaged with the ratchet member to prevent said opposite movement thereof; magnetic armature means including a driving pawl and means mounting the same to move both axially and laterally, the axial movement being toward and away from said ratchet member and the lateral movement being in a direction toward and away from said holding pawl means; a solenoid mounted so that said armature means can move both axially and laterally in the bore thereof; spring means normally urging said armature means to a position outwardy of said bore and away from said holding pawl means, momentary energization of the solenoid and cc-action of said spring means reciprocating said armature means axially to step said ratchet member by action of said driving pawl therewith; and electromagnetic means energizable to move said armature means laterally to dispose a part thereof toward and against said holding pawl to dislodge the latter from holding engagement with said ratchet member for release of the latter for opposite movement as aforesaid.

14. In an electromagnetic stepping mechanism, a driving pawl and means mounting the same for both axial and lateral directions of back-and-forth movement; magnetically attractable means coreciprocable with the driving pawl in both directions of movement thereof; a ratchet device cooperable with the driving pawl and advanced by axial reciprocation thereof; a releasably movable holding pawl spring-urged to normally engage with the ratchet device to prevent retrograde movement thereof; electromechanical means including a first electromagnet to act upon the magnetically attractable means of the driving pawl for axially reciprocating said pawl to advance the ratchet; and electromagnetic means energizable to act upon the magnetically attractable means of the driving pawl to displace the latter laterally into releasing engagement with said holding pawl and move the latter out of holding engagement with said ratchet device so that the latter can be moved retrogressively.

15. In an electromagnetic stepping mechanism for relays and the like, in combination, reversely movable ratchet means; a solenoid; an elongated armature structure reciprocable axially in the bore of said solenoid and of a lateral dimension to permit lateral displacement thereof in said bore; means mounting said armature structure for both axial and lateral motions; driving pawl means carried by said armature structure and moved by reciprocatory displacement of the latter in said bore to engage and advance said ratchet means from a predetermined starting position; means yieldingly acting to return said ratchet means to said starting position; releasable holding-pawl means yieldably urged into holding engagement with said ratchet means and movable in the direction of lateral displacement of said armature structure away from holding engagement as aforesaid with said ratchet means; said holding pawl being positioned in the path of lateral displacement of said armature structure to be engaged by the latter and moved to ratchet-releasing position responsive to lateral displacement of the armature structure; spring means acting on said armature structure to move the same both laterally and axially to a normal position in which said holding pawl is active to engage and hold said ratchet means, and said driving pawl means is disposed for axial reciprocation by coaction of said solenoid and spring means to engage and advance said ratchet means; together with magnetic means for shifting said armature structure laterally to release said holding pawl.

16. In an electromagnetic stepping mechanism, a reversely movable ratchet device; a holding pawl springurged to yieldingly and releasably engage with said ratchet device to prevent retrograde movement of the same; spring means yieldingly urging said ratchet device in the direction of retrograde movement to a predetermined normal position; drive-pawl means reciprocable co-directionally of the direction of movement of the ratchet device to advance same from starting position; magnetically attractable armature means rigidly attached to said drive pawl means and means mounting the same for both axial and lateral displacement; electromagnetic means for attracting said armature means in one direction of axial displacement; spring means driving said armature means in an opposite direction of axial displacement to complete reciprocation of the armature means cooperably with said electromagnetic means, said spring means also acting in a direction to displace said armature means laterally away from said holding pawl means; together with electromagnetic means operable independently of said first electromagnetic means for displacing the armature means laterally to engage said holding pawl means and move and release the latter from holding engagement with said ratchet means.

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